The present invention is directed to a method and device for providing respiration to a pateint which respiration is synchronized with the heart rhythm and which device and method promote the blood circulation.
In conventional respirator treatments, breathing gas is supplied to the lungs under pressure. This pressure is also partly propagated outside of the lungs into the body cavities in the thorax. It is known that this pressure essentially has a negative influence on the blood circulation. This negative influence is mainly based on the fact that the supply of blood to the heart and the filling of the chambers of the heart during the relaxation phase or expansion of the heart which is known as the diastole is impeded. An inadequate filling of the heart chambers, however, means that the heart cannot generate an adequate beat volume during the following contraction phase which is known as systole. When the heart activity of the blood circulation are already inadequate due to a disease, the negative influences caused by the respiration treatment can have serious consequences.
A series of proposals have already been made in order to reduce these harmful effects on the circulation. It is thus known that an adequate respiration can be achieved with a very high breathing rate, for example, several breaths per second. The volume of each breath is thus decreased and thus the pressure increases which disturb the blood circulation are reduced. This procedure is disclosed in an article in Proc. Am. Soc. Exp. Biol. Vol. 38, 1979, p. 951 and a prospectus Aga Bronchovent, 318.002 Sv, November 1978: Klain Jet Ventilator.
An additional known improvement can be achieved when the ventilation occurs synchronously with the heart activity so that one breath occurs at every heartbeat or at every second heartbeat. When the inhalation phase is thereby chronologically placed such that it coincides with the systole, an advantageous pressure increase around the heart can be achieved. At the same time, the pressure influence on the heart during the diastole is entirely or at least partially avoided so that the heart's activity is improved overall.
It is also known that the heart chambers can be emptied by means of external compression of the thorax and the heart chambers will again fill up upon removal of this compression. As a result thereof, a certain blood circulation can also be maintained even when the heart does not independently contract or when it is greatly diminished in this function of contraction.
A described possibility for reducing harmful effects on the blood circulation and for promoting the circulation are, however, limited. Given the high frequency ventilation in the heart rhythm, a low breath volume already produces a sufficient respiratioin so that only a slight intrathoracic pressure increase results. Even when this pressure increase is synchronized with the heart rhythm so that it appears during systole, only a slight positive effect is achieved.
Given an increase in the volume of each breath in order to achieve a more effective pressure increase, there exists a risk that the lungs may be damaged by the higher gas pressure to which they have been exposed. In addition, the lungs cannot be emptied fast enough given such a high volume for each breath.
An external compression of the thorax has the disadvantage that this can cause injury to the thorax itself or to internal organs. In addition, the external compression of the thorax may be painful to the patient.